Sheet-feeding device and image-forming apparatus

ABSTRACT

A sheet-feeding device and an image-forming apparatus incorporating the same. The sheet-feeding device includes a device body, a sheet storage unit that is detachably mounted in the device body, a tray for mounting sheets, the tray being provided at the sheet storage unit and being movable up and down, an air blower for blowing air laterally to the sheets mounted on the tray and floating the sheets, and a sucking and conveying unit for sucking and conveying the sheets floated by the air blower. The sheet storage unit is provided with a sheet regulation member so as to regulate rear ends of the sheets mounted on the tray. An upper end of the sheet regulation member is retractable downward.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet-feeding device and an image-forming apparatus, and more particularly, to a sheet-feeding device and an image-forming apparatus that may separate and feed sheets by blowing air to the sheets.

2. Description of the Related Art

Typically, image-forming apparatuses, such as a printer and a copier, include a sheet-feeding device that feeds sheets one by one from a sheet storage unit having a plurality of sheets stored therein. Such a sheet-feeding device may utilize a sheet-feeding method with air. With this method, air is blown to an end portion of a sheet bundle stored in the sheet storage unit to float several sheets, and a sucking and conveying belt disposed above sucks and conveys a single sheet. For example, Japanese Patent Laid-Open No. 7-196187 discloses a sheet-feeding device utilizing the sheet-feeding method with air.

FIG. 9 shows an example of such a sheet-feeding device utilizing the sheet-feeding method with air. As shown in FIG. 9, a sheet storage unit 11 for storing a plurality of sheets S is provided with a tray 12 for supporting the sheets S, the tray 12 being movable up and down. The sheet storage unit 11 is detachably provided at the device body. Sheets are supplied and replaced while the tray 12 is pulled out, and sheets may be fed while the tray 12 is mounted.

A sucking and conveying unit 50A is provided above the sheet storage unit 11, for sucking and conveying the sheets S. Also, an air blower 30 is provided at the upper portion of the sheet storage 11 for blowing air to the end portion of the sheet bundle on the tray 12 to float several sheets S and to separate the sheets S one by one.

The sucking and conveying unit 50A includes a sucking and conveying belt 21 and a suction fan 36. The sucking and conveying belt 21 is stretched between belt-driving rollers 41, for sucking a sheet S and conveying it rightward in the drawing. The suction fan 36 generates negative pressure so that the sucking and conveying belt 21 sucks the sheet S. The sucking and conveying unit 50A also has a suction duct 51 disposed at the inner side of the sucking and conveying belt 21, for sucking air through a suction hole made at the sucking and conveying belt 21. Further, the sucking and conveying unit 50A has a suction shutter 37 disposed between the suction fan 36 and the suction duct 51, for switching a suction operation of the suction fan 36 between ON and OFF states.

The air blower 30 includes a loosening nozzle 34A and a separation nozzle 34 for blowing air to the upper portion of the stored sheet bundle, a separation fan 31, and a separation duct 32 for sending air from the separation fan 31 to the nozzles 34A and 34.

Then, a part of the air sucked by the separation fan 31 in the direction of arrow C passes through the separation duct 32 and is blown in the direction of arrow D by the loosening nozzle 34A, to float several sheets located at the upper portion of the sheet bundle supported on the tray 12. The residual air is blown in the direction of arrow E by the separation nozzle 34 to separate the uppermost sheet of the several sheets floated by the loosening nozzle 34A, so that the sucking and conveying belt 21 sucks the sheet.

The position of the sheets mounted on the tray 12 are regulated by a rear-end regulation plate 13 for regulating the rear-end position in the sheet-feeding direction of the sheets, and by a side regulation plate 14 for regulating the position in the widthwise direction of the sheets, the widthwise direction being orthogonal to the sheet-feeding direction.

Accordingly, the position of the sheets can be regulated by the rear-end regulation plate 13 and the side regulation plate 14 even when the sheets are floated by the air blown from the air blower 30. Thus, the position of the floated sheets may be stabilized, and the uppermost sheet is sucked to an accurate position of the sucking and conveying belt 21.

Meanwhile, in the sheet-feeding device and image-forming apparatus of the related art, if the rear end of the sheet S is curled, or it is floated with irregular movement, the sheet S possibly exceeds the rear-end regulation plate 13 to be blown rearward (leftward in FIG. 9).

Owing to this, in the related art, the upper end T of the rear-end regulation plate 13 is determined to be higher than the height B of a sheet suction plane of the sucking and conveying belt 21, and an overlap distance δ, which is the difference between the height of the upper end T of the rear-end regulation plate 13 and the height B of the sheet suction plane of the sucking and conveying belt 21, is sufficiently secured. Accordingly, the sheet S may be prevented from exceeding the rear-end regulation plate 13 to be blown rearward, and it may be reliably loosened and sufficiently floated.

In a case where a thick sheet or the like is conveyed, the volume of loosening air is necessary to be increased for increasing loosening ability. However, if the volume of the loosening air is increased, the floating distance of the sheets is increased, and hence, the overlap distance δ is necessary to be a large value. As the overlap distance δ is increased, the height of the device is also necessary to be increased.

In the sheet storage 11, the rear-end regulation plate 13 is configured to be freely movable in the sheet-feeding direction so that the sheet storage 11 may store not only universal sizes and typical sizes, but also various sizes of sheets, including atypical sizes of sheets. This is a so-called free stop method, and it facilitates the positional setting of the rear-end regulation plate 13 for the user.

However, if the sheet storage 11 is inserted to the device body after the rear-end regulation plate 13 is moved to the position corresponding to the size of sheets, the rear-end regulation plate 13 possibly comes into contact with the sucking and conveying unit, a foreign substance detector (not shown), a cassette heater (not shown), and the like disposed above the sheet storage 11.

Accordingly, when moving with the sheet storage 11, it is necessary to prevent the rear-end regulation plate 13 from coming into contact with the sucking and conveying unit and the like. In particular, to allow the rear-end regulation plate 13 to move freely to the position corresponding to the size of sheets, it is necessary to prevent the rear-end regulation plate 13 from coming into contact with the sucking and conveying unit during its movement.

To avoid the contact between the rear-end regulation plate 13 and the sucking and conveying unit or the like, the height of the device is necessary to be increased. Therefore, as the separation ability (loosening ability) of the sheet-feeding device is increased, the device becomes large. That is, the reduction in size and the increase in separation ability (loosening ability) of the sheet-feeding device are conflicting factors.

SUMMARY OF THE INVENTION

The present invention is directed to a sheet-feeding device and an image-forming apparatus capable of increasing separation ability without an increase in size of the device.

In one aspect of the present invention, a sheet-feeding device includes a device body; a sheet storage unit that is detachably mounted in the device body; a tray configured to support sheets, the tray being disposed at the sheet storage unit and being movable up and down; an air blower configure to blow air to an end portion of the sheets supported by the tray so as to loosen the sheets; a conveying unit configured to convey the sheets supported by the tray; and a sheet regulation member disposed at the sheet storage unit and regulating the end portion of the sheets supported by the tray. An upper end of the sheet regulation member is retractable.

According to another aspect of the present invention, an image-forming apparatus includes an apparatus body; a sheet storage unit that is detachably mounted in the apparatus body; a tray configured to support sheets, the tray being disposed at the sheet storage unit and being movable up and down; an air blower configured to blow air to an end portion of the sheets supported by the tray so as to loosen the sheets; a conveying unit configured to convey the sheets supported by the tray; a sheet regulation member disposed at the sheet storage unit and regulating the end portion of the sheets supported by the tray; and an image-forming unit configured to form an image on the sheets conveyed by the conveying unit. An upper end of the sheet regulation member is retractable.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an image-forming apparatus provided with a sheet-feeding device according to an embodiment of the present invention.

FIG. 2 is an illustration explaining a configuration of a first sheet-feeding unit disposed in the image-forming apparatus.

FIG. 3 is an illustration showing an arrangement of a first sheet-feeding mechanism and a first sheet-feeding deck disposed in the first sheet-feeding unit.

FIGS. 4A and 4B are illustrations each showing a configuration of a rear-end regulation plate provided at the first sheet-feeding deck.

FIG. 5 is an illustration showing a state where a retraction member provided at the rear-end regulation plate is in contact with a frame of the sheet-feeding mechanism.

FIG. 6 is a first diagram explaining a state of the retraction member when the first sheet-feeding deck is mounted to the first sheet-feeding unit.

FIG. 7 is a second diagram explaining a state of the retraction member when the first sheet-feeding deck is mounted to the first sheet-feeding unit.

FIGS. 8A and 8B are illustrations each showing another configuration of the rear-end regulation plate.

FIG. 9 is an illustration explaining a configuration of a sheet-feeding device of the related art.

DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will be described with reference to the attached drawings.

FIG. 1 is a schematic illustration of an image-forming apparatus provided with a sheet-feeding device according to an embodiment of the present invention.

In FIG. 1, an image-forming apparatus 1A has an image-forming apparatus body 1 which includes a first sheet-feeding unit 4 and a second sheet-feeding unit 6 connected to each other in line. An escape unit 3 (described below) is disposed between the image-forming apparatus body 1 and the first sheet-feeding unit 4.

A delivery unit 5 is disposed between the first sheet-feeding unit 4 and the second sheet-feeding unit 6. The delivery unit 5 delivers a sheet from the second sheet-feeding unit 6 to the first sheet-feeding unit 4. A plurality of sheet-feeding units may be additionally connected in line at the upstream of the second sheet-feeding unit 6 if needed.

The image-forming apparatus body 1 has an electrophotographic image-forming unit 101A including a photosensitive drum 103 and so forth. The image-forming apparatus body 1 also has sheet-feeding devices 113A and 115A respectively having sheet-feeding decks 109 and 111 (sheet storage units) for storing sheets, and sheet-feeding mechanisms 113 and 115 for feeding the sheets stored in the sheet-feeding decks 109 and 111. In addition, registration rollers 119 are disposed upstream of the image-forming unit 101A. The registration rollers 119 correct obliqueness of a sheet and perform registration of a toner image on the photosensitive drum 103 and the sheet.

When the above-described image-forming apparatus body 1 starts an image-forming operation, the image-forming unit 101A forms a toner image on the photosensitive drum 103 by an exposure unit, a developing unit, etc. (not shown).

The sheets stored in the sheet-feeding decks 109 and 111 are conveyed to the registration rollers 119 by the sheet-feeding mechanisms 113 and 115 via a sheet-conveying path 117. Then, after the registration rollers 119 correct the obliqueness of the sheet, the sheet is conveyed to a position between the photosensitive drum 103 and a transfer roller 105 at a predetermined timing.

Accordingly, the toner image provided on the photosensitive drum 103 is transferred on the sheet at the position between the photosensitive drum 103 and the transfer roller 105. Then, the toner image is fixed to the sheet by heating and pressing the sheet by a fixing roller pair 107. The sheet with the toner image fixed is ejected from the image-forming apparatus body 1 by an ejecting roller 120.

The first sheet-feeding unit 4 includes first to third sheet-feeding decks 101, 201 and 301 (sheet storage units) for storing sheets. The first and second sheet-feeding decks 101 and 201 each can store about 1000 sheets, while the third sheet-feeding deck 301 can store about 2000 sheets. Each deck may be pulled out toward the front side of the device. The second sheet-feeding unit 6 has a configuration similar to that of the first sheet-feeding unit 4.

The first sheet-feeding unit 4 also includes first to third sheet-feeding mechanisms 151, 251 and 351 utilizing a sheet-feeding method with air for feeding sheets stored in the first to third sheet-feeding decks 101, 201 and 301. The first to third sheet-feeding mechanisms 151, 251 and 351, and the first to third sheet-feeding decks 101, 201 and 301 define sheet-feeding devices 151A, 251A and 351A, respectively.

The first to third sheet-feeding mechanisms 151, 251 and 351 send the sheets stored in the first to third sheet-feeding decks 101, 201 and 301 toward the image-forming unit 101A, selectively based on a signal given by a control device (not shown).

In FIG. 1, a first common conveying path 50 is provided horizontally between the first and second sheet-feeding decks 101 and 201. The first common conveying path 50 is linked to a second common conveying path 35 of the escape unit 3 and a third common conveying path 55 of the delivery unit 5.

First to third sheet-conveying paths 52, 54 and 56 for conveying the sheets from the first to third sheet-feeding decks 101, 201 and 301, are connected to the first common conveying path 50. A plurality of conveying roller pairs 58 are disposed in the first to third sheet-conveying paths 52, 54 and 56 at predetermined intervals. The conveying roller pairs 58 convey the sheets from the first to third sheet-feeding mechanisms 151, 251 and 351 along the first to third sheet-conveying paths 52, 54 and 56.

Also, a double-feeding detector 59 is disposed at a predetermined position in the first common conveying path 50. The double-feeding detector 59 detects an abnormal conveyance state, such as double feeding of the sheets to be conveyed. A signal output from the double-feeding detector 59 is input to the control device (not shown).

A flapper 33A (shown in FIG. 2) is provided at the bifurcation of the second common conveying path 35 and an escape conveying path 33. When the double-feeding detector 59 detects the double feeding of the sheets, the control device switches the position of the flapper 33A to the escape unit 3 side. Accordingly, the redundant sheet is ejected to an escape tray 38 through the escape conveying path 33 of the escape unit 3.

FIG. 3 is an illustration showing an arrangement of the first sheet-feeding mechanism 151 and the first sheet-feeding deck 101 disposed in the first sheet-feeding unit 4. The first sheet-feeding mechanism 151 employs a sheet-feeding method with air. With this method, air is blown to the sheets to loosen the sheets, and a sucking and conveying belt 407 sucks and conveys the loosened sheets. The second and third sheet-feeding mechanisms 251 and 351, and the second and third sheet-feeding decks 201 and 301 also have configurations similar to those of the first sheet-feeding mechanism 151 and the first sheet-feeding deck 101.

The first sheet-feeding deck 101 includes a tray 403 for mounting the sheets S to be stored, and a tray lift mechanism (not shown) for moving the tray 403 up and down between a downside position where the sheets S are supplied or replaced, and a sheet-feeding position where the sheets S are sent out.

Also, the first sheet-feeding deck 101 includes a side regulation plate 457 for regulating the widthwise position of the sheets S, and a rear-end regulation plate 458 (end regulation member) for regulating the rear-end position of the sheets S, i.e., the position of the sheets S at the upstream in the sheet-feeding direction. In this embodiment, the side regulation plate 457 and the rear-end regulation plate 458 may be freely moved in accordance with the size of sheets S. This is a so-called free stop method.

The first sheet-feeding deck 101 utilizing such a method may correspond to sheets having a width ranging from B5R to 14.33 inches (182 to 364 mm), and a length ranging from B5 to 19.2 inches (182 to 488 mm).

The first sheet-feeding mechanism 151 disposed above the first sheet-feeding deck 101 includes a sucking and conveying unit 151 a that sucks and conveys the sheets S mounted on the tray 403. The first sheet-feeding mechanism 151 also includes an air blower 151 b that floats the upper portion of the sheet bundle on the tray 403, and separates the sheets S one by one.

The sucking and conveying unit 151 a has a sucking and conveying belt 407 for sucking a sheet S and conveying the sheet S rightward in FIG. 3, a suction fan (not shown) for generating negative pressure to allow the sucking and conveying belt 407 to suck the sheet S, and the like. The sucking and conveying unit 151 a also has a suction duct 492 disposed at the inner side of the sucking and conveying belt 407, for sucking air through a suction hole (not shown) in the sucking and conveying belt 407.

The air blower 151 b includes a loosening nozzle 494 and a separation nozzle 493 for blowing air to the upper portion of the stored sheets S. The loosening nozzle 494 blows air toward the upper portion of the sheets mounted on the tray 403 to loosen the sheets. The separation nozzle 493 separates the uppermost sheet from the residual sheets loosened by the air blown from the loosening nozzle 494 so that the sucking and conveying belt 407 can suck the uppermost sheet.

As shown in FIGS. 4A and 4B, a retraction member 481 is retractably (slidably) provided at the upper portion of the rear-end regulation plate 458 of the first sheet-feeding deck 101. The retraction member 481 has guide grooves 481 d which are inclined by 45° for instance. Guide members 458 b provided at the rear-end regulation plate 458 are inserted to the guide grooves 481 d. The guide grooves 481 d and the guide members 458 b guide the retraction member 481 to slide in a direction 45° inclined relative to the rear-end regulation plate 458.

In addition, for instance, a retraction spring 482 (resilient member) is disposed between the rear-end regulation plate 458 and the retraction member 481. The retraction spring 482 has an end 482 a engaging a regulation member body 458 a of the rear-end regulation plate 458 and the other end 482 b engaging the retraction member 481. Due to the action of the retraction spring 482, the retraction member 481 protrudes upward in a normal state as shown in FIG. 4A. When being pressed, the retraction member 481 retracts toward the inside of the regulation member body 458 a.

Meanwhile, components, such as a foreign substance detector 153 and a cassette heater 152, are provided above the first sheet-feeding deck 101 as shown in aforementioned FIG. 2. The lower plane of such components including the foreign substance detector 153 and the cassette heater 152 is located below relative to the upper end of the retraction member 481.

Owing to this, when the rear-end regulation plate 458 is set at the position corresponding to the size of sheets S and then the first sheet-feeding deck 101 is inserted to the first sheet-feeding unit 4, the retraction member 481 possibly comes into contact with the foreign substance detector 153, the cassette heater 152, and the like.

If the retraction member 481 comes into contact with an obstruction, such as the foreign substance detector 153 and the cassette heater 152, the retraction member 481 is pressed by the obstruction, and retracts by sliding in the direction 45° inclined relative to the regulation member body 458 a of the rear-end regulation plate 458 as shown in FIG. 4B.

The downward retraction of the retraction member 481 when coming into contact with the obstruction allows the first sheet-feeding deck 101 to be set at a predetermined position in the first sheet-feeding unit 4 without being disturbed by the obstruction.

In this embodiment, through holes 481 a are formed at the retraction member 481 in the front-and-rear direction, so that the air blown from the separation nozzle 493 and the loosening nozzle 494 smoothly passes through the retraction member 481. Accordingly, laminar airflow is generated among the sheets at a portion between the rear-end regulation plate 458 and the nozzles 493, 494, and hence, the sheets are effectively loosened and separated.

If the rear-end regulation plate 458 opposes the separation nozzle 493 and the loosening nozzle 494, the sheets can be more effectively loosened and separated by utilizing the through holes 481 a.

Next, a state of the above-mentioned retraction member 481 at the insertion of the first sheet-feeding deck 101 will be described.

FIG. 3 shows a state where no obstruction is present above the rear-end regulation plate 458 that has been moved to the position corresponding to the size of sheets, namely, a state where the retraction member 481 does not come into contact with the obstruction. At this time, the retraction member 481 protrudes as in a normal state as shown in FIG. 4A.

In particular, when the first sheet-feeding deck 101 is inserted to the first sheet-feeding unit 4, the rear-end regulation plate 458 is set such that the retraction member 481 protrudes relative to a suction plane of the sucking and conveying belt 407 by an overlap distance 6. The overlap distance 6 is determined to be a height sufficient for holding the rear ends of the sheets even when the sheets are floated due to blowing of loosening air and separation air.

FIG. 5 shows a state where an obstruction, for example, a frame 151 c of the sheet-feeding mechanism 151, is present above the rear-end regulation plate 458 that has been moved to the position corresponding to the size of sheets. At this time, the retraction member 481 comes into contact with the frame 151 c of the sheet-feeding mechanism 151. Due to this, the retraction member 481 is pressed by the frame 151c, and becomes a retraction state as shown in FIG. 4B.

In particular, when the first sheet-feeding deck 101 is inserted to the first sheet-feeding unit 4, the rear-end regulation plate 458 is set such that the retraction member 481 retracts in the Z direction and comes into contact with the frame 151 c of the sheet-feeding mechanism 151.

At this time, the height of a regulation plane at the upper end of the rear-end regulation plate 458 defined by the retraction member 481 is decreased. However, since the retraction member 481 is in contact with the frame 151 c of the sheet-feeding mechanism 151, the sheets floated due to the blowing of the loosening air and the separation air will not exceed the regulation plane of the retraction member 481, thereby providing reliable regulation of the rear ends of the sheets.

FIGS. 6 and 7 are illustrations each explaining a specific operation for mounting the first sheet-feeding deck 101 to the first sheet-feeding unit 4, when viewed from the upstream in the sheet-feeding direction. In this case, the sheet-feeding mechanism 151 overlaps with the retraction member 481 when the first sheet-feeding deck 101 is inserted to the first sheet-feeding unit 4 from the front side.

Accordingly, as shown in FIG. 6, when the first sheet-feeding deck 101 is inserted to the first sheet-feeding unit 4 from the front side, the sheet-feeding mechanism 151 becomes an obstruction, and the retraction member 481 comes into contact with an end surface 151 d of the frame 151 c of the sheet-feeding mechanism 151. When the first sheet-feeding deck 101 is further inserted, the retraction member 481 is pressed by the frame 151 c and retracts downward with 45° inclination. Then, the first sheet-feeding deck 101 slides while being in contact with the lower surface of the sheet-feeding mechanism 151, and is set as shown in FIG. 7.

Depending on the size of sheets, the retraction member 481 possibly comes into contact with a downwardly protruding portion, such as the cassette heater 152 and the foreign substance detector 153 (FIG. 2), and may retract downward accordingly.

If no obstruction is present above the rear-end regulation plate 458 as shown in FIG. 3 when the first sheet-feeding deck 101 is set, the retraction member 481 protrudes due to the retraction spring 482. In such state, the upper end of the retraction member 481 is higher than the suction plane of the sucking and conveying belt 407 by the distance δ.

As described above, since the retraction member 481 is provided at the upper portion of the regulation member body 458 a so as to be vertically movable, the rear-end regulation plate 458 can maintain the height sufficient for regulating and holding the rear ends of the floated sheets at the position with no obstruction being present above. On the other hand, at the position with an obstruction being present, the upper end of the retraction member 481 may retract downward since it comes into contact with the obstruction.

Accordingly, the rear ends of the sheets may be reliably regulated, and separation ability of the sheets may be increased, without an increase in height of the device. As a result, reliability of a sheet-feeding device utilizing air may be markedly enhanced, and reduction in size of the device is significantly promoted.

FIGS. 8A and 8B each show another configuration of the rear-end regulation plate. In FIGS. 8A and 8B, two retraction members 581 are provided at the upper portion of a regulation member body 558 a of a rear-end regulation plate 558 so as to be swingable about shafts 581 a.

The two retraction members 581 are biased to protrude upward due to retraction springs 582 (resilient members) in a normal state. FIG. 8A shows a case where the rear-end regulation plate 558 is inserted to a position with no obstruction of the device body. FIG. 8B shows a case where the rear-end regulation plate 558 is inserted to a position overlapping with that of the obstruction of the device body. In short, when the obstruction is present, the two retraction members 581 retract toward the inside of the regulation member body 558 a.

Since the retraction members 581 are swingable, the retraction members 581 may be moved further smoothly. In addition, since the pair of retraction members 581 is provided, an area for pressing the rear ends of the sheets may be increased, thereby further reliably regulating the rear ends of the sheets.

In the above exemplary embodiment, while the present invention is applied to the rear-end regulation plate for regulating the rear ends of the sheets at the sheet-feeding device utilizing the sheet-feeding method with air, the present invention is not limited thereto, and may be applied to the following configuration.

For example, there may be provided a configuration having an air blower for blowing air to the end portion of sheets, the end portion extending in the widthwise direction orthogonal to the sheet-feeding direction, and a side regulation plate for regulating the opposite end portion of the sheets. In such a configuration, the upper end of the side regulation plate may be configured to retract downward. Also, without limiting to the sheet-feeding device utilizing the sheet-feeding method with air, sheets may be fed by a roller. In such a configuration, the present invention may be applied to an end regulation plate for regulating sheets supported by a tray.

In the above exemplary embodiment, while the sheets are fed by sucking and conveying with the use of the sucking and conveying belt, the present invention is not limited thereto. For example, the present invention may be applied to a configuration with other separation method, such as one utilizing a generally-used inverse roller. In such a configuration, air is blown to the end portion of sheets for preparatorily loosening the sheets for reliable feeding.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions.

This application claims the benefit of Japanese Application No. 2006-102580 filed Apr. 3, 2006, which is hereby incorporated by reference herein in its entirety. 

1. A sheet-feeding device comprising: a device body; a sheet storage unit detachably mounted in the device body; a tray configured to support sheets, the tray being disposed at the sheet storage unit and being movable up and down; an air blower configured to blow air to an end portion of the sheets supported by the tray so as to loosen the sheets; a conveying unit configured to convey the sheets supported by the tray; and a sheet regulation member disposed at the sheet storage unit and regulating the end portion of the sheets supported by the tray, wherein an upper end of the sheet regulation member is retractable.
 2. The sheet-feeding device according to claim 1, wherein the conveying unit includes a sucking and conveying unit configured to suck and convey sheets that are floated by the air blown from the air blower.
 3. The sheet-feeding device according to claim 1, wherein the sheet regulation member includes a regulation member body and a retraction member disposed at an upper portion of the regulation member body and being retractable downward, and the sheet storage unit is mounted in the device body while the retraction member retracts downward by a member disposed at the device body.
 4. The sheet-feeding device according to claim 3, further comprising a resilient member, wherein the retraction member is slidably provided at the regulation member body, and is biased in a protruding direction by the resilient member.
 5. The sheet-feeding device according to claim 3, further comprising a resilient member, wherein the retraction member is swingably provided at the regulation member body, and is biased in a protruding direction by the resilient member.
 6. An image-forming apparatus comprising: an apparatus body; a sheet storage unit detachably mounted in the apparatus body; a tray configured to support sheets, the tray being disposed at the sheet storage unit and being movable up and down; an air blower configured to blow air to an end portion of the sheets supported by the tray so as to loosen the sheets; a conveying unit configured to convey the sheets supported by the tray; a sheet regulation member disposed at the sheet storage unit and regulating the end portion of the sheets supported by the tray; and an image-forming unit configured to form an image on the sheets conveyed by the conveying unit, wherein an upper end of the sheet regulation member is retractable.
 7. The image-forming apparatus according to claim 6, wherein the sheet regulation member includes a regulation member body and a retraction member disposed at an upper portion of the regulation member body and being retractable downward, and the sheet storage unit is mounted in the device body while the retraction member retracts downward by a member disposed at the device body. 